Anchor wedge configuration for tendon anchors
A wedge for a tendon retaining anchor includes at least two circumferential wedge segments adapted to be placed on an exterior of a tendon. The wedge segments have an exterior surface adapted to cooperate with a receiving bore of a load transfer device and an interior surface having gripping elements thereon. A circumferential dimension of the wedge segments is selected so that a total uncompressed gap between circumferential ends of the wedge segments when the segments are applied to an exterior surface of the tendon is at most about 2.4 times a height of the gripping elements. In another aspect, a tendon retaining system includes an anchor having a wedge receiving bore and wedge segments adapted to cooperate with the wedge receiving bore. The wedge segments include gripping elements on an interior surface thereof. The system includes a device adapted to limit lateral compression of the wedge segments.
1. A post tensioned concrete tendon retaining wedge, comprising:
at least two circumferential wedge segments adapted to be placed on an exterior of a tendon, the wedge segments having an exterior surface adapted to cooperate with a receiving bore in a load transfer device, the wedge segments having an interior surface having gripping elements thereon, a circumferential dimension of the wedge segments selected so that a total uncompressed gap between circumferential ends of the wedge segments when the segments are applied to an exterior surface of the tendon at most 2.4 times a height of the gripping elements, wherein an exterior surface of the tendon and an interior surface of the gripping elements define substantially the same radius of curvature, such that when the wedge segments are laterally compressed against the tendon, the circumferential ends of the wedge segments contact each other.
2. The wedge of claim 1 wherein the uncompressed gap is within a range of about 0.24 to at most 2.4 times the height of the gripping elements.
3. The wedge of claim 1 wherein the uncompressed gap is within a range of about 0.4 to 1.8 times the height of the gripping elements.
4. The wedge of claim 1 wherein the uncompressed gap is at most 0.050 inches for a nominal 0.500 inch outer diameter tendon.
5. The wedge of claim 4 wherein the uncompressed gap is at most 0.021 inches.
6. The wedge of claim 1 wherein the gripping elements comprise threads.
7. The wedge of claim 6 wherein the threads comprise buttress threads.
8. A post tensioned concrete reinforcement system, comprising: an anchor plate having at least one generally tapered bore therein; and
at least two circumferential wedge segments, each segment defining an exterior tapered surface and an interior surface, the exterior surface adapted to cooperatively engage with the at least one tapered bore on the anchor plate, the interior surface having gripping elements thereon, a circumferential dimension of the wedge segments selected so that a total uncompressed gap between circumferential ends of the wedge segments when the segments are applied to an exterior surface of a tendon is at most 2.4 times a height of the gripping elements, wherein an exterior surface of the tendon and an interior surface of the gripping elements define substantially the same radius of curvature, such that when the wedge segments are laterally compressed against the tendon, the circumferential ends of the wedge segments contact each other.
9. The system of claim 8 wherein the uncompressed gap is within a range of about 0.24 to at most 2.4 times the height of the gripping elements.
10. The system of claim 8 wherein the uncompressed gap is at most 0.4 to 1.8 times the height of the gripping elements.
11. The system of claim 10 wherein the uncompressed gap is at most 0.021 inches.
12. The system of claim 8 wherein the gripping elements comprise threads.
13. The system of claim 12 wherein the threads comprise buttress threads.
14. A post tensioned concrete reinforcement system, comprising:
an anchor plate having at least one generally tapered bore therein;
at least two circumferential wedge segments, each segment defining an exterior tapered surface and an interior surface, the exterior surface adapted to cooperatively engage with the at least one tapered bore on the anchor plate, the interior surface having gripping elements thereon; and
a compression limiting device cooperatively engaged with the wedge segments, the compression limiting device configured to limit lateral compression of the wedge segments when the segments are applied to an exterior surface of a tendon to at most 2.4 times a height of the gripping elements.
15. The system of claim 14 wherein the lateral compression of the wedge segments is limited to within a range of about 0.24 to at most 2.4 times the height of the gripping elements.
16. The system of claim 15 wherein the lateral compression of the wedge segments is limited to within a range of 0.4 to 1.8 times the height of the gripping elements.
17. The system of claim 14 wherein the gripping elements comprise threads.
18. The system of claim 17 wherein the threads comprise buttress threads.
19. The system of claim 14 wherein the compression limiting device comprises at least one spacer adapted to be disposed between circumferential ends of the wedge segments, a thickness of the at least one spacer and gaps between circumferential ends of the wedge segments selected to limit the lateral compression.
20. The system of claim 14 wherein the compression limiting device comprises a device for limiting axial motion of the wedge segments into the anchor.
21. The system of claim 20 wherein the axial motion limiting device comprises a taper angle subtended by the tapered bore that is less than a corresponding taper angle subtended by the exterior surface of the wedge segments, the axial motion limiting device further comprising serrations on the exterior surface of the wedge segments.
22. The system of claim 20 wherein the axial motion device comprises a shoulder formed into the tapered bore cooperatively engaged with the wedge segment to limit axial motion thereof.
23. A post tensioned concrete reinforcement system, comprising:
at least two circumferential wedge segments adapted to be placed on an exterior of a tendon, the wedge segments having an exterior surface adapted to cooperate with a receiving bore in a load transfer device, the wedge segments having an interior surface having gripping elements thereon, a circumferential dimension of the wedge segments selected so that a total uncompressed gap between circumferential ends of the wedge segments when the segments are applied to an exterior surface of the tendon at most 2.4 times a height of the gripping elements wherein an exterior surface of the tendon and an interior surface of the gripping elements define substantially the same radius of curvature, an axial length of the wedge segments equal to at most 2 . 3 times a nominal diameter of the tendon, such that when the wedge segments are laterally compressed against the tendon, the circumferential ends of the wedge segments contact each other.
24. The system of claim 23 wherein the uncompressed gap is within a range of about 0.24 to at most 2.4 times the height of the gripping elements.
25. The system of claim 23 wherein the uncompressed gap is within a range of about 0 . 4 to 1 . 8 times the height of the gripping elements.
26. The system of claim 23 wherein the uncompressed gap is at most 0.050 inches for a nominal 0.500 inch outer diameter tendon.
27. The system of claim 26 wherein the uncompressed gap is at most 0.021 inches.
28. The system of claim 23 wherein the axial length is at most 1.15 inches for a nominal 0.500 inch outer diameter tendon.
29. The system of claim 23 wherein the gripping elements comprise threads.
30. The system of claim 29 wherein the threads comprise buttress threads.